The present invention relates to an eccentric worm pump with a helical worm rotor which rolls off in planetary fashion in a hollow helix, adapted to its cross-section and its pitch, of a stator sleeve. Between the rotor and the facing portion of the hollow helix, closed helical cavities are formed and are moved from an intake end to a delivery end of the stator sleeve.
Eccentric worm pumps are used for widely varying purposes, particularly for the delivery of pulpy highly viscous material and goods containing solid particles. They are self-aspirating and can generate relatively large pressures which depend on the ratio of stator length to pitch. The goods to be transported are partially crushed or homogenized, and solid particles are ground, or, if the stator is made of resilient material such as rubber, they are partially transported without undergoing change. From the roll-off process between rotor and stator, there result relatively large pressure and friction loads which frequently lead to very quick wear on the inside contour of the stator helix. Even with radial position of the stator sleeve, the wear is sometimes so large that the stator sleeve must be replaced after a very short period. The operating costs for the pumps are relatively large due to such repairs.
Accordingly, it is an object of the present invention to reduce the wear on eccentric worm pumps and to lower their operating cost.
Another object of the present invention is to provide an eccentric worm pump of the foregoing character which is substantially simple in construction and may be economically fabricated.
A further object of the present invention is to provide an eccentric worm pump, as described, which may be readily maintained in service and which has a substantially long operating life.